#define DMAX 0.005

gopen(640, 400, gcolor("green"), 1);
gwindow(0, 1.25, 2, 0);

gflush(False);

costbl = new real[6];
sintbl = new real[6];

for(a = 0; a < 6; a++)
{
    costbl[a] = cos(a * M_PI / 3);
    sintbl[a] = sin(a * M_PI / 3);
}

gpset(0, 0);
x = y = 0.0;
d = 2.0;
a = 0;
koch();
gpause();

function koch()
{
    if(d <= DMAX)
    {
	x += d * costbl[a % 6];
	y += d * sintbl[a % 6];
	gline(x, y);
    }
    else
    {
	d /= 3.0; koch(); a++; koch();
	a += 4;	  koch(); a++; koch();
	d *= 3.0;
    }
}